Pathogenic viruses can be classified into two general types with respect to the viral structure: enveloped viruses and non-enveloped viruses. Some well-known enveloped viruses include herpes virus, influenza virus; paramyxovirus, respiratory syncytial virus, corona virus, HIV, hepatitis B virus, hepatitis C virus and SARS-CoV virus. Non-enveloped viruses, sometimes referred to as “naked” viruses, include the families Picornaviridae, Reoviridae, Caliciviridae, Adenoviridae and Parvoviridae. Members of these families include rhinovirus, poliovirus, adenovirus, hepatitis A virus, norovirus, papillomavirus, and rotavirus.
It is known in the art that “enveloped” viruses are relatively sensitive and, thus, can be inactivated by commonly used disinfectants. In contrast, non-enveloped viruses are substantially more resistant to conventional disinfectants and are significantly more environmentally stable than enveloped viruses. Although a number of non-enveloped viruses can be inactivated with relatively high concentrations of formaldehyde, the use of formaldehyde is undesirable because of its toxicity.
The non-enveloped virus Norovirus (NoV), also known previously as “Norwalk-Like Virus” (NLV) or small round structured virus, is the most important viral pathogen of epidemic acute gastroenteritis that occurs in both developed and developing countries. NoV belongs to the Caliciviridae family and are icosahedral, single stranded, positive-sense RNA viruses whose capsids are composed of 180 copies of a single major structural protein. Noroviruses are estimated to cause 23 million cases of acute gastroenteritis in the United States per year, and are the leading cause of gastroenteritis in the United States. Of viruses, only the common cold is reported more often than viral gastroenteritis (norovirus). Norovirus causes nausea, vomiting (sometimes accompanied by diarrhea), and stomach cramps. This infection typically is spread from person to person by direct contact.
Noroviruses are very highly contagious and can spread easily from person to person. People can become infected with the norovirus in several ways, including, eating food or drinking liquids that are contaminated with norovirus; touching surfaces or objects contaminated with norovirus, and then placing their hands in their mouths; or having direct contact with another person who is infected and showing symptoms (for example, when caring for someone who is ill, or sharing foods or eating utensils with someone who is ill). During outbreaks of norovirus gastroenteritis, several modes of transmission have been documented, for example, initial foodborne transmission in a restaurant, followed by secondary person-to-person transmission to household contacts. No evidence suggests that norovirus infection occurs through the respiratory system.
Protracted outbreaks of norovirus disease have been reported among elderly persons living in institutional settings, e.g., nursing homes. In some cases, the outbreak was initially caused by exposure to a fecally-contaminated vehicle (e.g., food or water). Then, the outbreak spreads through person-to-person transmission among the residents. This spread is facilitated by the enclosed living quarters and reduced levels of personal hygiene that result from incontinence, immobility, or reduced mental alertness. Because of underlying medical conditions, the disease among these elderly persons can be severe or fatal.
Passengers and crew members on cruise ships and naval vessels are frequently affected by outbreaks of gastroenteritis. Cruise ships often dock in countries where sanitation levels are inadequate, thus increasing the contamination risk of water and food taken aboard or having a passenger board with an active infection. After a passenger or crew member brings the norovirus on board, the close living quarters on ships amplify opportunities for person-to-person transmission. Furthermore, the arrival of new and susceptible passengers every few days or weeks on affected cruise ships provides an opportunity for sustained transmission during successive cruises. Norovirus outbreaks extending beyond twelve successive cruises have been reported.
Currently, no antiviral medication against norovirus is available, and no standard method to prevent infection exists. Norovirus infection cannot be treated with antibiotics. Noroviruses also are relatively resistant to environmental challenge. Noroviruses can survive freezing, temperatures as high as 60° C., and even have been associated with illness after being steamed in shellfish. Moreover, noroviruses can survive in up to 10 ppm chlorine, which is well in excess of chlorine levels routinely present in public water systems. Accordingly it is an object herein to provide a composition for inactivation of non-enveloped viruses that is may be used topically on skin and can also function as a hard surface cleaner.
It is yet another object of the invention to provide a composition and method for viral inactivation of non-enveloped viruses that results in a greater than 3 log reduction of a population.
Other objects, aspects and advantages of this invention will be apparent to one skilled in the art in view of the following disclosure, the drawings, and the appended claims.